类型为List的模型的属性 <int> 尽管传递的值为null，但仍从POST实例化

Question

I'm using ajax to perform a post to an action with this declaration:

public ActionResult MonitorReport(FilterCaseViewModel model)

Amongst other things the FilterCaseViewModel has this property:

public class FilterCaseViewModel
{
    public List<int> Status { get; set; }
}

I'm using JSON for the content type, The JSON object starts like this (I've omitted the rest of it as it's quite long).

{ model: {"TextSearch":null,"Generic1":null,"Generic2":null,"Status":null,"Team":null,"Client":null

Looking at the request form I'm getting an empty string interpreted for Status

Despite this however the Status property has been instantiated and a value of 0 has been added to the list.

I would expect the Status property to be null , why is this not the case?

Note: Status is not set anywhere in the constructor.

Answer 1

Any integer in .net by default will hold 0 as a value. If you need a null as a default value of an integer variable, you need to define it nullable. Like this-

int? i;

More details can be found here - Using Nullable Types (C# Programming Guide)